breach-check

breach-check is a command for coding agents from Awarexone/Agentic-Bug-Hunter. It costs 79 tokens per session (1,006 once invoked), scanned A, original, MIT.

A command that checks passwords in a wordlist against Have I Been Pwned, a service that reports whether passwords have appeared in known data breaches, and ranks them by breach count.

In plain words
What is it for?
Filtering or ranking a password wordlist, optionally showing breach counts, and selecting passwords within chosen minimum or maximum count limits.
Why use it?
It helps identify passwords with evidence of real-world use while sending only a partial password hash through the service's k-anonymity process.

Command

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/awarexone/agentic-bug-hunter/breach-check
Clone the repo
git clone --depth 1 https://github.com/Awarexone/Agentic-Bug-Hunter

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for breach-check

README.md
[![agentmods](https://agentmods.dev/badge/commands/awarexone/agentic-bug-hunter/breach-check.svg)](https://agentmods.dev/commands/awarexone/agentic-bug-hunter/breach-check)
Your own site
<a href="https://agentmods.dev/commands/awarexone/agentic-bug-hunter/breach-check"><img src="https://agentmods.dev/badge/commands/awarexone/agentic-bug-hunter/breach-check.svg" alt="Measured on agentmods" height="20"></a>
Per session 79 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,006 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00079 $0.01006
Opus 5 $0.00039 $0.00503
Sonnet 5 $0.00016 $0.00201
Haiku 4.5 $0.00008 $0.00101

Measured 4d ago against content hash 0486d3cb90c7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

breach-check scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

Pure Python 3.9+, no external deps (uses urllib + hashlib + ThreadPoolExecutor from stdlib).
commands/breach-check.md · 87 lines

How it starts

The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/breach-check

Rank a password wordlist by HaveIBeenPwned breach count. Used between /wordlist-gen and spray to surface which candidates have proven human use.

Usage

/breach-check recon/target.com/wordlists/ranked.txt
/breach-check ranked.txt --with-counts                              # also dump TSV
/breach-check ranked.txt --max-count 1000000                        # drop generic passwords (>1M)
/breach-check ranked.txt --min-count 1                              # only keep proven-real passwords
/breach-check ranked.txt --limit 5000                               # test/preview first 5k (lex-sorted slice)
/breach-check ranked.txt --limit 5000 --shuffle                     # random 5k sample (avoid ASCII-sort bias)

What this does

For each password in the wordlist:

  1. Compute SHA-1 hash
  2. Send only the first 5 chars to api.pwnedpasswords.com/range/{prefix} (k-anonymity)
  3. HIBP returns ~500 candidate suffix-count pairs
  4. Match locally to get exact breach count for your password

Privacy: HIBP never sees the full password. Add-Padding header is used to obscure prefix distribution from network observers.

Why rank by breach count

Range Meaning Spray strategy
0 Never leaked Could be company-specific OR truly random — context-dependent
1–1000 "Sweet spot" — proven human use but not yet in every spray list Prioritize — high signal/cost ratio
1k–1M Mainstream password Usually already tried by previous attackers
>1M Generic ("password", "123456") Skip — every WAF expects these, lockout risk

Example (real HIBP results)

209,972,844    123456                ← generic, drop
 52,256,179    password              ← generic, drop
 30,799,395    qwerty                ← generic, drop
  1,505,362    Password123           ← generic-ish
  1,406,394    letmein               ← generic-ish
        180    flexdemo              ← SWEET SPOT — real but rare
          0    twilio2025            ← company-specific, untested
          0    xpkqwmnvbzabc12345    ← random, untested

Read the full file on GitHub · 87 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 87 lines · 79 tokens per session scan A 0486d3cb90c7

Subscribe to this mod's changes

breach-check is a command published in the GitHub repository Awarexone/Agentic-Bug-Hunter (4,689 stars, last pushed 2d ago), licensed MIT. It adds 79 tokens to every session and 1,006 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

Other commands, from other repositories

recon

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elementalsouls/Claude-BugHunter · 65 tokens

hunt

Active vulnerability hunting. Two-track dispatcher — asks Red Team vs WAPT, hands off to hunt-dispatch skill and sibling commands. Usage: /hunt target.com | /hunt .target.com | /hunt targets.txt [--vuln-class X] [--source-code P] [--chrome].

elementalsouls/Claude-BugHunter · 63 tokens

token-scan

Meme coin and token security scan — checks for rug pull vectors (hidden mint, honeypot, fee manipulation, LP lock bypass, authority retention, bonding curve exploits, fake renounce, sandwich amplification). Manual 8-class grep audit (with an optional automated scanner if present). Usage: /token-scan [--chain solana].

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autopilot

Run autonomous hunt loop on a target — scope check → recon → rank surface → hunt → validate → report with configurable checkpoints. Usage: /autopilot target.com [--paranoid|--normal|--yolo].

elementalsouls/Claude-BugHunter · 49 tokens

triage

Quick 7-Question Gate triage on a finding before writing a report. Kills N/A submissions before they happen. Faster than /validate — for quick go/no-go decisions. Usage: /triage.

elementalsouls/Claude-BugHunter · 45 tokens

validate

Validate a finding — runs 7-Question Gate + 4-gate checklist. Kills weak findings before report writing. Prevents N/A submissions that hurt validity ratio. Usage: /validate.

elementalsouls/Claude-BugHunter · 41 tokens